Trigger for machine guns



June 7, 1938. s. e. GREEN 2,119,536

TRIGGER FOR MACHINE GUNS Filed July 14, 1937 26 19 l {W 3 29 a2 /3 5 0 27 I 7 C I M l" 20 -/4 Inventor Samuel ELBr'EETL 2y h/WF Att mrney Patented June 7, 1938- NHTED STTES PAT E OFFIQE 11 Claims.

(Granted under the act of March 3, 1883, as

amended April 30, 1928; 3'70 G. 757) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to a trigger for machine guns.

The Browning machine gun, model of 1917, is provided with a trigger in the form of a simple lever which provides for automatic firing so long as it is held in the raised or firing position. Firing is interrupted only by releasing the trigger, but due to rapid action of the gun it is impossible to control single-shot firing.

The purpose of this invention is to provide a trigger which is capable of automatic and semiautomatic firing, which is simple and inexpensive, which may be readily installed to replace the present Browning trigger without altering the gun or modifying its normal action, and which in operation maintains the throw, pull and all characteristics of the present trigger.

These purposesare accomplished by providing a trigger in the form of a compound lever and a slide which is moved into inoperative position when it is desired to fire automatically, and into operative position when it is desired to fire semiautomatically. The trigger is so arranged that on its initial movement the sear-engaging portion moves downwardly to withdraw the sear and on its continued movement the sear-engaging portion moves upwardly and is restored. to neutral position. This restoration to neutral position during the continuous pull on the trigger is very desirable because of the rapid action of the breech bolt of the gun.

To these and other ends, the invention consists in the construction, arrangement and combination of elements described hereinafter and pointed out in the claims forming a part of this specification.

A practical embodiment of the invention is illustrated in the accompanying drawing, wherein:

Fig. l is a View of the rear portion of a Browning gun, partly in side elevation and partly in section, and showing the improved trigger in the neutral position.

Fig. 2 is a view with the rear end of the trigger raised.

Fig. 3 is a view with the rear end of the trigger raised and pivoted on the back plate.

Fig. 4 is a plan view of the trigger with the parts as shown in Fig. 1.

Figs. 5 and 6 are views in rear elevation showing the position of adjustment of the slide with respect to the trigger.

Referring to the drawing by characters of reference there is shown a portion of a machine gun of the Browning type including receiver A having a back plate B, lock frame C, and reciprocating breech bolt D which carries the sear E.

The trigger of the Browning gun is similar to the trigger F forming the subject of this invention except that it is a simple lever, whereas the improved trigger is a compound lever consisting of a front lever 5 and a rear lever 6 connected by a pivot pin 1. The front lever 5 is mounted on the lock frame by the conventional pivot pin 8 which is in the form of a plunger capable of engaging a recess 9 (Fig. 4) in the receiver to hold the lock frame in place. The cam lugs l0 (Fig. 3) on the forward end of the lever 5 and the complementary cam lugs H on the sear are the same as in the original gun, the lugs l0 being above and forwardly of the lugs The rear portion of the front lever 5 consists of a downwardly extending arm I2 which is inserted in the front part of a channel I 3 in the rear lever 6 and when assembled thereto by the pivot pin I its bottom face is spaced from the floor of the channel. A set screw l4 threaded in the arm projects from the front face thereof and is adapted to engage the plate I5 of the lock frame to limit upward movement of the front arm of the lever 5 and determine the neutral position of the cam lugs Ill. The arm I2 is provided with a recess for receiving a spring I6 and plunger ll, the plunger engaging the floor of the channel l3. The plunger is located rearwardly of the pivot pin 1.

The rear face of the arm I2 is formed with a notch I8 for receiving the head IQ of a latch which is slidably mounted in the channel l3 of the rear lever 6. The latch is formed with a longitudinally extending recess 2| and a transverse slotl22 at the rear of the recess 2|. A-pin 23 fixed in the rear lever passes through the slot 22 to limit and guide movement of the latch and form a seat for a spring 24 which is housed in the recess 2|. The front end of the spring is confined by a plug 25 which closes the front of the recess 2|. A pin 26 is fixed in the rear lever forwardly of the pin 23 and above the latch and assists in holding the latch in the channel.

The rear end of the latch is provided on its upper side with a cam 21, which, when the latch is in the forward position, is disposed directly in rear of the back plate B, the trigger passing through a slot 28 in the back plate as in the original gun. A slide 29 replacing the trigger lock or safety catch of the original gun is similarly mounted and is movable transversely of the back plate. The left hand portion 30 of the slide has its lower edge in line with the upper edge defining the slot 28 while the right hand portion 31 has its lower edge above the upper edge of the slot. The right hand portion is in the form of a spring finger with a rib 32 for selectively engaging either of two recesses 33-33 to hold the slide in position of adjustment. A rib 34 at the right end of the portion 30 serves as a thumb piece for moving the slide and in one position of adjustment of the slide its lower face 35 is disposed in the path of upward movement of the cam 21.

The front and rear levers and 6 when assembled are normally in the relative positions shown in Fig. 1, the latch being slightly retracted by the arm l2 of the front lever, and the head IQ of the latch being engaged in the notch I8. When the trigger is mounted in the lock frame through the pivot pin 8, the portion of the rear lever which extends through the slot 28 rests on the floor of the receiver and the cam lugs iii are in the neutral position.

When it is desired to fire automatically the slide 29 is moved to the left so that no portion of it will be in the path of movement of the cam 2'! on the latch when the rear end of the trigger is raised. In this position of adjustment of the slide the trigger functions in the same manner as the simple trigger of the original gun, the front and rear levers 5 and 6 being locked by the latch and moving as a unit on the pivot pin 8. Upon raising the rear end of the trigger the cam lugs It act on the cam lugs II of the sear to depress the sear. If the trigger is held in the firing position the gun will be fired automatically in the conventional manner every time that the breech bolt moves into battery, it being understood that the firing pin is cooked and the sear elevated to reengage it during reciprocation of the breech bolt.

When it is desired to fire semi-automatically, the slide 29 is moved to the right to position the rib 34 in the path of movement of the cam 21 on the latch, when the rear end of the trigger is raised. Upon raising the rear end of the trigger the cam 21 is acted on by the rib 34 to retract the latch. During the first part of this movement the trigger moves about the pivot pin 8 and functions in the usual manner to depress the sear for the reason that the front and rear levers 5 and 6 are locked together by the head [9 of the latch 20. But as soon as the latch is completely withdrawn from the notch in the front lever the continued pressure on the rear end of the rear lever 6 causes this lever to move about the pivot pin 1 and during its final movement the latch is further retracted. When the rear lever has been moved to the top of the slot 28 it engages the back plate and continued pressure causes the lever to pivot on the back plate thereby lowering its front end and with it the pivot pin 1. Since the pivot pin 1 is engaged with the arm l2 of the front lever, the front lever will be swung about the pivot pin 8 in a reversed direction until the set screw l4 engages the plate l5. The front lever is now restored to the neutral position (Fig. 3) where it is incapable of depressing the sear as the breech bolt moves into battery. As the front lever is moved to neutral position the arm I2 is lowered so that.

the latch is positively prevented from moving forward to reestablish the connection so long as the rear lever is in the raised position.

Upon releasing the rear lever it will immediately drop due to gravity and the action of the spring-pressed plunger l1 and the latch reengages the front lever. The parts are now in the position shown in Fig. 1 and the trigger must be again raised in order to fire the next round.

I claim:

1. In a machine gun, a receiver having a floor and a back plate with a recess, a frame in the receiver, a trigger comprising a rear lever and a front lever, the rear lever having a channel and extending through the recess in the back plate, the front lever having a sear-engaging front portion and a depending arm at its rear, said arm inserted in the channel of the rear lever and having a notch in its rear face, a pivot pin connecting the arm and the rear lever, a

pivot pin carried by the frame and mounting the front lever forwardly of the rear arm, an adjustable stop on the arm and engageable with the frame to limit movement of the front lever in one direction, a spring-pressed plunger between the arm and the channel floor of the rear lever, a latch slidable in the channel of the rear lever and having a head receivable in the notch of the arm, a spring normally holding the latch in engagement with the arm to maintain the front lever in neutral position and holding the head of the latch in the notch to couple the front and rear levers for unitary movement, a cam lug on the rear of the latch, and a slide on the latch movable into position to be engaged by the cam lug and effect retraction of the latch when the rear end of the trigger is raised.

2. In a machine gun, a receiver having a floor and a back plate with a recess, a frame in the receiver, a trigger comprising pivotally connected rear and front levers, the rear lever extending through the recess in the back plate and the front lever having a sear-engaging front portion, a pivot pin carried by the frame and mounting the front levers forwardly of its pivotal connection with the rear lever, a latch slidably carried by the rear lever, a spring normally holding the latch in engagement with the front lever to maintain the front lever in neutral position and to couple the levers for unitary movement, a cam on the latch, a slide on the latch movable into inoperative position and into operative position to be engaged by the cam and effect retraction of the latch when the rear end of the trigger is raised, and a resilient member between the front and rear levers and normally tending to depress the rear lever. V

3. In a machine gun, a receiver having a floor and a back plate with a recess, a frame in the receiver, a trigger comprising pivotally connected rear and front levers, the rear lever extending through the recess in the back plate and the front lever having a sear-engaging front portion, a pivot pin carried by the frame and mounting the front lever forwardly of its pivotal connection with the rear lever, a latch slidably carried by the rear lever, a spring normally holding the latch in engagement with the front lever to maintain the front lever in neutral position and to couple the levers for unitary movement, a cam on the latch, a slide on the latch movable into inoperative position and into operative position to be engaged by the cam and effect retraction of the latch when the rear end of the trigger is raised.

4. In a gun, a support, a trigger comprising carried by the rear lever, a spring normally holding the latch in engagement with the front lever to maintain the front lever in neutral position and to couple the levers for unitary movement, said latch being normally slightly retracted by the front lever, cooperating means on the latch and support for retracting the latch when the rear end of the trigger is raised and a resilient mem ber between the front and rear levers, and normally tending to separate the adjoining ends of the levers.

5. In a gun, a support, a trigger comprising rear and front levers, a pivot pin connecting said levers, a pivot pin carried by the support and mounting the front lever forwardly of its pivotal connection with the rear lever, a latch slidably carried by the rear lever, a spring normally holding the latch in engagement with the front lever to maintain the front lever in neutral position and to couple the levers for unitary movement, cooperating means on the latch and support for retracting the latch when the rear end of the trigger is raised and a resilient member between the front and rear levers, and normally tending to separate the adjoining ends of the levers.

6. In a gun, a support, a trigger comprising rear and front levers, a pivot pin connecting said levers, a pivot pin carried by the support and mounting the front lever forwardly of its pivotal connection with the rear lever, .a latch slidably carried by the rear lever, a spring normally holding the latch in engagement with the front lever to maintain the front lever in neutral position and to couple the levers for unitary movement, said latch being normally slightly retracted by the front lever, cooperating means on the latch and support for retracting the latch when the rear end of the trigger is raised.

'7. In a gun, a support, a trigger comprising rear and front levers, a pivot pin connecting said levers, a pivot pin carried by the support and mounting the front lever forwardly of its pivotal connection with the rear lever, a latch slidably carried by the rear lever, a spring normally holding the latch in engagement with the front lever to maintain the front lever in neutral position and to couple the levers for unitary movement, cooperating means on the latch and support for retracting the latch when the rear end of the trigger is raised.

8. In a gun, a support, a trigger comprising rear and front levers, a pivot pin connecting said levers, a pivot pin carried by the support and mounting the front lever forwardly of its pivotal connection with the rear lever, a latch slidably carried by the rear lever and normally engaging the front lever to couple the rear and front levers for unitary movement, means on the latch and support for uncoupling the levers from unitary movement when the rear end of the trigger is raised.

9. In a gun, a support, a trigger comprising rear and front levers, a pivot pin connecting said levers, a pivot pin carried by the support and mounting the front lever forwardly of its pivotal connection with the rear lever, a latch normally coupling the levers whereby they are movable as a unit to displace the front lever from neutral to firing position, a slide having an inoperative position and movable into an operative position to effect retraction of the latch when the rear end of the trigger is raised and to uncouple the levers, and a surface on the support serving as a fulcrum for the rear lever whereby continued pressure on the rear lever effects reversal of the front lever to neutral position, and a resilient member between the front and rear levers and normally tending to separate the adjoining ends of the levers.

10. In a gun, a support, a trigger comprising rear and front levers, a pivot pin connecting said levers, a pivot pin carried by the support and mounting the front lever forwardly of its pivotal connection with the rear lever, a latch normally coupling the levers whereby they are movable as a unit to displace the front lever from neutral to firing position, a slide having an inoperative position and movable into an operative position to effect retraction of the latch when the rear end of the trigger is raised and to uncouple the levers, and a surface on the support serving as a fulcrum for the rear lever whereby continued pressure on the rear lever effects reversal of the front lever to neutral position.

11. In a gun, a support, a trigger comprising rear and front levers, a pivot pin connecting said levers, a pivot pin carried by the support and mounting the front lever, means normally coupling the levers whereby they are movable as a unit, and means operable during the final portion of the firing movement of the trigger to inoperate the coupling means.

SAMUEL G. GREEN. 

